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Pool Salt Calculator.
Calculate salt mass from pool volume, salinity change, and product purity.
Set your values
Results update as you type.
Results update automatically as you type. Every quantity and convention is an explicit input; no local prices, sizing charts, or usage defaults are inferred.
FAQs
What assumptions does this calculator use?
Calculate salt mass from pool volume, salinity change, and product purity. Every quantity, unit, and convention is entered explicitly; no local pricing, sizing chart, or usage default is inferred.
Use Cases
Adjusting pool salinity for a salt chlorine generator
When your salt cell reads low, use this calculator to determine how much salt to add to bring the level back to the recommended range.
Example: For a 20,000-gallon pool needing a 500 ppm increase with 99% pure salt, the calculator shows you need about 83 lbs.
Planning salt addition for a new pool fill
When filling a new pool, you can calculate the initial salt dose to reach the desired starting salinity.
Example: For a 15,000-gallon pool wanting 3,200 ppm from zero with 100% pure salt, you'd need roughly 400 lbs.
Frequently Asked Questions
- How does the pool salt calculator work?
- It uses your pool volume, the desired change in salinity (in ppm), and the purity of your salt product to compute the mass of salt required. The formula accounts for the fact that 1 ppm in a given volume corresponds to a specific weight, adjusted for purity.
- What units does the calculator use?
- The calculator accepts pool volume in gallons or liters, salinity change in parts per million (ppm), and salt purity as a percentage. It then outputs the required salt mass in pounds or kilograms, depending on your input.
- Why is salt purity important?
- Salt products vary in purity; for example, some contain anti-caking agents. Using a lower purity means you need more product to achieve the same salinity increase. The calculator adjusts for this to give an accurate mass.
Tips & Common Mistakes
Tips
- Always test your pool's current salinity before adding salt to avoid over- or under-dosing.
- Add salt in increments and retest after the salt has dissolved and circulated for 24 hours.
- Use high-purity pool salt (at least 99%) to minimize impurities that can affect water chemistry.
- For best results, broadcast the salt evenly across the pool surface and brush to help it dissolve.
Common Mistakes to Avoid
- Assuming all salt is 100% pure; check the label and adjust for purity to avoid underdosing.
- Using the pool's total volume instead of the actual water volume, which may be less due to displacement by people or features.
- Adding salt directly to the skimmer or near the return jet, which can cause damage; always add to the pool's deep end.
Last updated: August 13, 2026